Methods of constructing fluid-tight tanks or like holders, and tanks obtained therefrom

ABSTRACT

967,753. Storing liquefied gas. GAZ DE FRANCE. July 26, 1961 [Aug. 10, 1960], No. 27165/61. Heading F4P. A liquefied gas storage chamber 3 is excavated from a pit 2 dug in the ground and water is injected around the chamber during the filling thereof with liquefied gas to form about the chamber a layer of frozen water or of a watersoaked and frozen material. An inspection plate 5 is supported in a circular recess 4 in the pit 2 and piping 6, 7 and 8 for removing fluid from the chamber extends through the plate 5. Holes 9, 10, 11 and 12 are provided for injecting the water; the lower ends of the holes may lie close to the pit 2 and the chamber 3. Heat probes 13, 14 and 15 may be provided so that the temperature of the ground may be taken. A layer of sand or loose rocks or stones is disposed on the&#39;plate 5, and this layer may be sprinkled with water so that it will freeze and form a fluid-tight seal. The water is preferably injected when the chamber walls are at a temperature below 32‹ F.

Oct 16, 1962 J. TocHE 3,058,316

METHODS oF coNsTRucTrNG FLUID-TIGHT TANKS 0R LIKE HOLDERS, AND TANKS OBTAINED THEREFROM Filed July ze, 1961 United States Patent O 3,058,316 METHGDS F CONSTRUCTING FLUlD-TIGH'I TANKS 0R LIKE HOLDERS, AND TANKS OBTAENED THEREFROM Jean Toche, Chatou (Seine et Oise), France, assignor to Service National dit: Gaz de France Filed duly 26, 1961, Ser. No. 127,039 Claims priority, application France Aug. 10, 1960 4 Claims. (Cl. 62-45) The present invention relates essentially to a method of constructing fluid-tight tanks or like holders of the type designed notably for storing liquefied gases or other substances at very low temperature.

The multivarious problems arising from the storage of substances or liquids at very low temperature, notably liqueed gases, are well known. In general the liquefied gas or like fluid is stored in an excavation dug in the ground at a temperature such that its vapour pressure approximates the atmospheric pressure. Thus, during a normal working period the actual pressure in the tank is relatively low, for example less than 14 p.s.i.

Now it is obvious that this new method of storing substances of the type referred to hereinabove is attended by many advantages over the known conventional methods. However, the practical actuation of this new method is attended by difficulties chiefly in connection with Huid-tightness.

It is therefore an essential object of this invention to provide a method whereby these difficulties can be overcome, which is remarkable notably in that it consists primarily in lining the walls of the tank with a layer consisting either of frozen water or of a material firstly water-soaked and then frozen.

According to another feature characterizing this invention the freezing step is carried out by utilizing the influence of the low temperature prevailing in the tank proper.

According to Ia further feature of this invention, water is injected around the tank before or during the filling thereof with liquefied or like gas.

It is another feature of this invention to effect the injection preferably from the time when the tank walls have attained a temperature of 32 F.

From the foregoing it will be readily understood that by using extremely simple means, namely the freezing of water due to the action of the low temperature of the very gases to be stored, it is possible to construct tanks wherein the pressure may be kept at relatively high values without the slightest inconvenience.

This invention is also concerned, by way of novel industrial products, with tanks co-nstructed according to the method broadly set forth hereinabove.

Other features of this invention will appear as the following description proceeds with reference to the accompanying drawing of which the single FIGURE illustrates diagrammatically by way of example `and in longitudinal axial section a tank constructed according to the teachings of this invention.

In the example illustrated in the drawing the reference numeral 1 designates the ground level from which a pit or well Z of any desired and suitable depth has been dug- If necessary, the pit walls are lined or provided With adequate propping means of which the only function is to support the soil material during the excavation. At the lower end of the pit or from the base thereof a storage chamber 3 having the requisite volume is dug. The walls of this chamber 3l may also be provided with suitable propping means, if necessary.

At the bottom of the pit and at the upper portion of the tank-forming chmber 3 a circular groove or like 3,058,316 Patented Oct. 16, 1962 recess 4 is formed in order to provide a shoulder adapted to support a lfloor-forming plate 5i. This plate is not compulsorily made of fluid-tight material since its only purpose is to permit the passage of piping such as. 6, 7 and 8 for taking fluid out from the tank and inspect the llatter when necessary.

When the tank or chamber 3 has been excavated, sounding holes 9, 10, 11 and -12 for example are bored for injecting water, as will be explained presently. If desired, these sounding holes may have their lower end located in close proximity of the well 2 and chamber 3, and they are simply connected to a source of water under pressure (not shown). If desired, the installation may be completed by providing heat probes shown in diagrammatic form at 1"3, 14, and `15.

Upon Acompletion of the mounting of piping 6, 7 and 8, -a layer of sand or loose rocks or stones is disposed on the floor-forming plate 5, this layer consisting preferably of the same material as that constituting the ground in which the pit and chamber 2, 3 have been excavated. These stones, rocks or sand may be humidiiied or sprinkled with water. Thereafter the tank is iilled with a low-temperature liquid, for example a liquefied gas, and at the same time water is injected through the sounding holes 9, 10, 11 and 12. Under these conditions a freezing process develops which is distributed concentrically from the tank outwards, and the adjacent soi-l material will thus constitute a fluid-tight barrier whereby the gas can be stored under a certain pressure Well above the atmospheric value. Simultaneously, the floor-forming plate 5A is also frozen and constitutes a duid-tight sealed closure member plugging the pit.

The only care required is to avoid that an excessive quantity of water accumulates `in the bottom of the tank. This Water may be thawed and raised through any suitable and known pumping means.

The most favourable case is that in which the ground is initially soaked with Water. In this case the digging is carried out after the ground has been frozen according to the 'conventional method, without changing the steps involved in the process of forming the tank and freezing its walls for tightness purposes.

It will be noted that water may be injected either before introducing the liquefied gas, or preferably when the temperature of the tank walls has dropped to less than 32 F.

Of course, this invention should not be construed as being limited to the single form of embodiment described hereinabove and illustrated in the accompanying drawing, as many modifications, notably in connection with the shape and the relative proportions of the pit 2' and chamber 3 and with the arrangement of the piping and bores, may be brought thereto Without departing from the spirit and scope of the invention as set forth in the appended claims.

What I claim is:

l. In a method of of constructing a fluid tight enclosed space for storing under pressure a substance at very low temperatures, the steps of digging a cavity deep in the ground, la pit leading from said cavity to the ground surface, of closing said cavity by means of a floor-forming plate adapted in said pit at the bottom thereof and provided with openings, of mounting through said openings the necessary piping for said cold substance, of covering said floor-forming plate with a water-soaked material which subsequently freezes and forms a fluid tight layer solid with the walls of said pit.

2. Method according -to claim l wherein said watersoaked material consists of stony, rocky and sandy material.

3. A fluid tight enclosed space for storing under pressure a substance at very low temperatures comprising a cavity dug in a Water-soaked ground, a pit leading from said cavity to the ground surace, a door-forming plate 4adapted in said pit substantially where said pit merges in said cavity, openings in said floor-forming plate, pipings for said substance extending through said openings, a layer of water-soaked material on said `floor-forming plate in said pit at the bottom of the latter, said watersoaked material in said pit yand ground around said cavity being frozen and constituting a continuous duid-tight layer surrounding said cavity.

4. A iluid tight enclosed space for storing under pressure a substance at very low temperatures according to d claim 3 wherein said cav-ity dug deep in the ground is substantially spherical whereas said pit is vertical and substantially cylindrical, said spherical cavity having a diameter which is much larger than the diameter of said cylindrical pit.

References Cited in the le of this patent UNITED STATES PATENTS 2,796,739 Meade et al. June 25, 1957 2,932,170 Patterson et a1. Apr. 12, 1960 2,961,840 Goldtrap Nov. 29, 1960 

